JP2002363544A - Process for producing spherical projecting material, and projecting material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for economically producing a dense spherical nonmetallic projecting material which withstands repeated uses and generates little waste material, and a projecting material produced by the process. SOLUTION: The process for producing a spherical projecting material comprises a step of producing a reactant by mixing an iron oxide powder with a powder containing 30 mass% or more metallic aluminum, or producing a reactant by mixing them and molding the mixture, a reaction step of igniting the reactant as it is, or mixed with one or more kinds of powders selected from MgO, ZrO2 , SiO2 and Al2 O3 powders to cause a thermit reaction, a step of granulating molten oxide(s) produced by the thermit reaction into a spherical form, and a step of classifying the granulated particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for industrially producing a blasting material used for shot blasting and a blasting material produced by the method.

[0002]

2. Description of the Related Art Shot blasting is a processing method in which abrasive particles called a shot material are projected onto the surface of a workpiece at high speed.
A wide range of castings, steel, shipbuilding, automobiles, aircraft, electricity, electronics, etc. for the purpose of removing foreign substances such as molding sand, scale, paint, etc. on the surface of the workpiece, matte finishing of the surface skin, cleaning or improving fatigue life. Used in industrial fields. Projectiles used for shot blasting include metal-based and non-metallic-based blasting materials, each of which has significantly different characteristics such as finished performance and required cost. Therefore, at the time of shot blasting, a shot material having an optimum material and particle size is selected from the viewpoint of the purpose of shot blasting, physical and chemical properties of a workpiece, required finishing performance and cost, and the like.

[0003] Examples of metal-based projectiles include steel, stainless steel, aluminum, and zinc. These metal-based projectiles are all widely used because they are adjusted to an optimum chemical composition as a projectile, subjected to heat treatment as needed, and can withstand repeated use. However, the metal-based blast material is worn by the projection to generate slight fine powder, and if the fine powder adheres to and remains on the workpiece, there may be a problem in the finishing performance of the workpiece. In such a case, a metal-based projection material of the same material as the workpiece is usually used, but when there is no material of the same material, a non-metal-based projection material has been used.

[0004] Non-metallic projection materials include natural ore-based materials such as silica sand and olivine sand, and artificial ones such as alumina and slag. This is used when cost is prioritized because of the risk of occurrence of blasting or not using the blasting material repeatedly. Originally, shot blasting used natural ore-based projectiles, also called sandblasting, but natural ore-based projectiles were very brittle against impact, so the consumption of projectiles was severe, so when shot blasting There is a problem that a large amount of waste is generated. Furthermore, natural ore-based projectiles such as silica sand containing free silicic acid have problems such as causing silicosis, and their use has been rapidly decreasing in recent years.

[0005] Alumina-based projectiles, one of the non-metallic projectiles, are produced by melting, solidifying and pulverizing alumina from bauxite as a raw material. There is a disadvantage that the production cost is high because of the necessity. Also, in the first place, alumina-based blasting materials are industrially manufactured mainly for abrasive grains for grinding wheels, and part of them are used as blasting materials, so they are necessary to withstand repeated use as blasting materials. It is inferior in impact resistance, and has a defect that it is heavily consumed due to the fact that a large amount of cracks generated in the pulverizing step at the time of manufacturing are incorporated therein.

[0006] Slag-based projectiles are the most widely used among nonmetallic projectiles because they are relatively inexpensive. Examples include copper slag, nickel slag, ferronickel slag, and ferrochrome. There are slag and steel slag. All of these slag-based projectiles are produced by subjecting molten slag generated during metal refining to water granulation or air-blasting.These projectiles are relatively inexpensive because they are only by-products, Adjustment is not possible due to the chemical composition of the metal being refined. Therefore,
It is difficult to make the chemical composition of the slag-based blasting material suitable for the blasting material, and therefore, there is a problem that the slag-based blasting material is inferior in impact resistance, is greatly consumed, and generates large amounts of waste.

[0007] As described above, non-metallic projectiles have a large common problem that they generate a large amount of waste. In recent years, in particular, in recent years, due to the tightness of landfill disposal sites, they have a long service life that can withstand repeated use. There is a strong demand for inexpensive non-metallic blasting materials that generate little matter. Generally, the shape of the blast material is longer than the shape of the irregularly pointed sphere. If the metal-based projection material can be manufactured, the above-mentioned problems of the conventional projection material can be solved. However, conventionally, since a large amount of energy was required to melt the high melting point oxide, it was extremely difficult to produce a long-life nonmetallic blasting material at low cost.

[0008]

SUMMARY OF THE INVENTION The present invention provides a method for inexpensively producing a dense, spherical, nonmetallic projection material that can withstand repeated use and generates little waste, and a projection material produced by the method. The task is to

[0009]

Means for Solving the Problems According to the first aspect of the present invention, which has been made to solve the above-mentioned problems, an iron oxide powder and a powder containing metallic aluminum are mixed to produce a reactant, or A reactant producing step of producing a reactant by molding a mixture after mixing powder containing iron oxide powder and metallic aluminum; and causing a thermite reaction to occur by igniting the reactant, or a method of producing MgO, ZrO ₂ , Si
A reaction step of causing a thermite reaction by igniting one or more powders of O ₂ and Al ₂ O ₃ , and a molten oxide produced by the thermite reaction, And a classification step of classifying the granulated particles to collect particles having a desired particle size.

According to a second aspect of the present invention, a reactant is manufactured by mixing iron oxide powder and powder containing metallic silicon, or a mixture is formed after mixing powder containing iron oxide powder and metallic silicon. Reactant manufacturing process to produce a reactant by
A thermite reaction is caused by igniting the reactant, or MgO, ZrO ₂ , SiO ₂ , Al ₂
A reaction step of causing a thermite reaction by igniting the above-mentioned reactant to which one or more powders of O ₃ is added, and a step of granulating the molten oxide produced by the thermite reaction into spherical particles. The method is characterized by comprising a granulating step and a classifying step of collecting particles having a desired particle size by classifying the granulated particles.

According to a third aspect of the present invention, in the first aspect of the present invention, the powder containing metallic aluminum contains metallic aluminum in an amount of 30% by mass or more, and the equivalent circle diameter of the particles is 10 mm or less. It is characterized by the following. Note that the equivalent circle diameter of the particles means a diameter when non-spherical particles such as a rod, an ellipsoid, a ribbon, and a needle are regarded as spherical particles having the same volume.

According to a fourth aspect of the present invention, in the second aspect, the powder containing metallic silicon contains metallic silicon in an amount of 30% by mass or more, and the equivalent circle diameter of the particles is 10 mm or less. It is characterized by the following.

The invention according to claim 5 is characterized in that, in the invention according to any one of claims 1 to 4, the method for granulating the molten oxide produced by the thermite reaction into spherical particles is wind milling. Is what you do.

According to a sixth aspect of the present invention, the chemical composition has a quality
Al%_TwoO_Three: 80-20%, SiO_Two: 80 ~
10%, MgO, CaO, MnO, FeO, F
e_Two O_Three, Cr_TwoO_Three, ZrO_Two, TiO_Two, Na_TwoO and
K_TwoThe total of O is 20% or less, and the particle size is 0.05 to
2. It is between 80 mm and described in any one of claims 1 to 5.
Characterized by being manufactured by the method for manufacturing a spherical projection material described above.
Spherical projectile.

According to a seventh aspect of the present invention, the chemical composition is such that, in mass%, MgO: 70 to 10%, SiO ₂ : 70% or less, Al ₂ O ₃ : 70% or less, and CaO, Mn
_{O, FeO, Fe 2 O 3} , Cr 2 O 3, ZrO 2, TiO
_2, the total of Na ₂ O and K ₂ O is more than 20%, particle size be between 0. 05 to 2. 80 mm, claim 1
5. A spherical projection material manufactured by the method for manufacturing a spherical projection material according to any one of 5.

[0016] The invention according to claim 8, chemical composition, in mass%, ZrO _2: 70~10% between, SiO _2: 70
%, Al ₂ O ₃ : 70% or less, MgO, C
_{aO, MnO, FeO, Fe 2} O 3, Cr 2 O 3, TiO
_2, the total of Na ₂ O and K ₂ O is more than 20%, particle size be between 0. 05 to 2. 80 mm, claim 1
5. A spherical projection material manufactured by the method for manufacturing a spherical projection material according to any one of 5.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The oxidized form of iron FeO, Fe ₃
There are three types, O ₄ and Fe ₂ O ₃ , and these forms of iron oxide react with metallic aluminum as follows.

(Equation 1) First, the reactant producing step in the method for producing a spherical blasting material of the present invention comprises the step of mixing an iron oxide powder and a powder containing a predetermined amount of metallic aluminum according to the form of the iron oxide powder, thereby forming an oxidant generated by a thermite reaction. The purpose of this is to prepare a reactant whose composition is optimal as a shot material. In the thermite reaction, the theoretical mixing ratio of metallic aluminum to iron oxide differs depending on the form of iron oxide, but in any case, if the mixing ratio of metallic aluminum is greater than the theoretical amount, excess metallic aluminum remains in the iron, Conversely, if the mixing ratio of metallic aluminum is less than the theoretical amount, excess iron oxide will remain in Al ₂ O ₃ .

The present invention intends to produce a blasting material using an oxide produced by a thermite reaction. Aluminum remaining in iron does not cause any problem, but oxidation in Al ₂ O ₃ produced by the reaction is not affected. It is necessary to keep the iron content in a range that does not adversely affect the quality of the shot material. For this reason, the mixing ratio of the powder containing metallic aluminum to the iron oxide powder is 0.24 times as much as the weight of metallic aluminum in the powder and the weight of FeO for each type of iron oxide.
0.33 times, 0.29 times per weight of Fe ₃ O ₄
Preferably, the ratio is 0.32 times to 0.44 times with respect to 0.40 times and the weight 1 of Fe ₂ O ₃ . When the iron oxide powder comprises a plurality of forms of iron oxide, the compounding ratio of the powder containing metallic aluminum can be easily determined based on the compounding ratio for each form of iron oxide.

Since metallic silicon causes the following reaction called a silico-thermit reaction similarly to metallic aluminum, a part or all of the metallic aluminum-containing powder is mixed with metallic silicon-containing powder, for example, a particle circle. It is also possible to prepare a reactant in place of metal silicon powder having an equivalent diameter of 10 mm or less or ferrosilicon powder.

(Equation 2) As a raw material of the reactant used in the reactant production process, it is of course possible to use an industrially produced raw material, but from the viewpoint of providing an inexpensive shot material of the present invention, it is advantageous in terms of production cost. It is preferable to use inexpensive raw materials, especially wastes or wastes. As the inexpensive iron oxide powder, iron oxide generated as waste from processes such as steelmaking / smelting, heat treatment, forging, and shot blasting can be used. A coarse material such as a scale generated in a heat treatment or a forging process can be used as a raw material of the reactant as it is, but it is preferable to use the material after being crushed to 0.2 mm or less in advance.

As the powder containing inexpensive metal aluminum, aluminum scraps such as aluminum dust and waste such as dust collected from aluminum shot blast and aluminum polishing powder can be used. Generally, the metal silicon in addition to oxides, such as aluminum scrap Al ₂ O _3, magnesium, contains metals such as copper or manganese, Al ₂ O ₃ is a thermite reaction product
Of course, these metals do not affect the quality of the projectile. Like metallic aluminum, metallic silicon and magnesium in metallic aluminum react with iron oxide powder to form oxides and remain in Al ₂ O ₃ to constitute components of the shot material. Further, a metal such as manganese having a relatively small standard free energy of formation of an oxide with iron or a metal which is easily reduced such as copper remains in the iron generated by the thermite reaction as it is. Therefore, the powder containing metallic aluminum of the present invention can be used as a raw material of a reactant without any problem as long as metallic aluminum is contained in an amount of 30% by weight or more. The equivalent circle diameter of the powder particles suitable for the reactant is 10 mm or less. If the equivalent circle diameter of the aluminum scrap or waste particles exceeds 10 mm, the equivalent circle diameter of 10 mm or less is obtained by grinding in advance. It is preferable to use it after adjustment.

In the present invention, an additive which does not directly participate in the thermite reaction may be added to the reactant in the reaction step in order to make the shot material have a desired chemical composition. If the additive is present in a large amount, the thermite reaction may be delayed or the reaction itself may be difficult to occur in the case of a powdered reactant, but it is effective to form the reactant into a block as a countermeasure. is there. The shape of the formed reactant may be any form such as briquette, pellet or rod, and the formation can be performed using a general granulator, for example, a briquetting machine.

In the method for producing a spherical projection material according to the present invention,
In the reaction step, a molten oxide with a chemical composition suitable for the shot material is obtained
Refractory material that is not easily eroded by molten iron and molten oxide during the process
Add the reactant or reactant to the lined reaction vessel
Additives are loaded and used by standard means such as electric spark
Ignite the reactants causing a thermite reaction
Let As an additive, it is preferred as a component of the shot material.
MgO powder, ZrO_Two Powder, SiO_TwoPowder, Al_TwoO_ThreePowdery
Use any powders or powders of their composition
You. The additive SiO_TwoPart or all of the powder
In addition, metal silicon powder in an amount corresponding to the amount of Si in advance,
Or powder containing metallic aluminum as ferrosilicon powder
By preparing a reactant in place of_TwoPowder addition
It is also possible to obtain a molten oxide having the same chemical composition as described above.

In the thermite reaction, a temperature exceeding 2700 ° C. can be obtained, but the amount of the additive is so large that the heat of the thermite reaction alone is insufficient to cause a problem in the granulation in the next granulation step. It is preferable to perform preheating using a fuel such as LPG gas or heavy oil before ignition. In a short time after the ignition, a molten iron layer is formed separately at a lower portion of the reaction vessel and a molten oxide layer is formed at an upper portion thereof by a thermite reaction and its reaction heat. After the completion of the reaction, the additive is melted by the heat of thermite reaction, and is uniformly mixed in the molten oxide layer by a bumping phenomenon that occurs during the reaction. The raw material of the additive used in this step is not limited to the raw material produced industrially, and the waste lining material of the melting furnace, fine waste sand generated in the reprocessing of the waste ceramic or the blasting material, etc. are pulverized as necessary. The waste can also be used, and if such waste is used as a raw material for the additive, the production cost can be significantly reduced. If the waste used as an additive contains a component involved in the thermite reaction, for example, iron oxide or the like in an amount of 1% by mass or more, an amount of aluminum powder corresponding to the component and the content is previously added to the reactant. Preferably, it is added to the mixture or mixed with additives.

In the present invention, iron oxide powder derived from waste is also used as a reactant raw material, but generally, iron oxide powder generated as waste contains components specific to the generation process. For example, steelmaking dust includes ZnO, PbO, CdO, Ca
O, SiO ₂ , Cr ₂ O ₃ , MnO and the like are contained.
Normally, steelmaking dust has a harmful component of lead and cadmium dissolved out of the landfill standard. Therefore, the dust is detoxified and then disposed of in landfill, or zinc, lead and cadmium are recovered. The residue after the recovery treatment is used as a raw material for ironmaking only in a small amount of residual Zn and Cr, but most of the residue cannot be used as a raw material for ironmaking and is disposed of in landfill. In the present invention, Z contained in steelmaking dust
nO, PbO and CdO are reduced and vaporized by thermite reaction and the heat of the reaction, and then re-oxidized by contacting with air and collected in a dust collector in a powder state. Recovered ZnO, Pb
Dust collected from O and CdO can be used as a raw material for refining zinc. Other metal oxides such as Cr ₂ O ₃ , MnO, and NiO contained in the iron oxide powder are reduced during the thermite reaction and recovered in the molten iron. As described above, the present invention enables not only the use of iron oxide powder containing harmful components generated as waste but also the recovery of valuable metal resources.

The granulating step in the method for producing a spherical projectile according to the present invention is a step of granulating the molten oxide to a particle size suitable for the projected material particles. This is performed by utilizing the property that the oxide stream is broken into droplets and the droplets become spherical due to surface tension. The principle of this step is basically the same as the spraying of molten metal, and it is possible to use various spraying methods used for producing spherical metal powder in this granulation step. Although various spraying methods can be applied to the granulation of the molten oxide, in order to prevent the generation of non-spherical particles, a cooling function such as water, which tends to solidify before the crushed droplets become spherical, is used. A method using a gas having a small cooling capacity as a spray medium, for example, air crushing, is preferable to a method using a spray medium having a large cooling capacity.

The classifying step in the method for producing a spherical projection material of the present invention is a step of classifying the granulated spherical particles to recover spherical particles having a particle size of 0.05 to 2.80 mm suitable for the projection material. Classification can be performed by a general method such as a sieve. Spherical particles generated in this step and having a particle size unsuitable for a blasting material can be reused as they are or after being pulverized and used as an additive in the reaction step. Regular shaped particles can also be used. Such irregularly shaped particles have lower impact resistance than spherical particles, but can be used as a shot blasting material in which grinding performance is important.

[0027]

The present invention will be specifically described below with reference to examples. (Example 1) As a raw material of a reactant, a hot forged scale obtained by pulverizing a scale generated when hot forging steel, a powder containing metallic aluminum generated in an aluminum can regenerating process, and a sand regenerating process as an additive The dust collected in the above was used. Table 1 shows the chemical composition of the hot forged scale, Table 2 shows the chemical composition of the powder containing metallic aluminum, and Table 3 shows the chemical composition of the dust collection dust.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

A reactant was prepared by mixing 1 kg of the pulverized hot forged scale and 370 g of powder containing metallic aluminum with a fine mixer. After 150 g of dust collected by sand recycling treatment was added to the reactant and charged in a graphite crucible, a heat-retaining sleeve piece heated and ignited with an acetylene touch was charged into the graphite crucible to ignite the reactant. Immediately after the termination of the thermite reaction, the molten oxide in the graphite crucible was granulated using compressed air of 0.5 MPa. After the particles were cooled to room temperature, the particles were classified using sieves having meshes of 0.05 mm and 3.35 mm. As a result, the chemical composition was 59.8% for Al ₂ O ₃ , 33.7% for SiO ₂ , and the remainder was MgO. _{CaO, MnO, FeO, Fe 2} O 3, Cr
A ₂ O _3, ZrO _2, a mixture of TiO _2, Na ₂ O and K ₂ O, to give a dense spherical projection material particle size 0. 05~2. 80mm. The impact strength (average number of shots up to crushing) of this spherical projectile was compared and investigated using an Irvine life tester at a projection speed of 32 m / sec. Is a piece of quartz sand
It was 20 times.

Example 2 As a raw material of a reactant, dust collected in a shot blasting process for producing polished steel bars,
A powder obtained by pulverizing dust collected from aluminum roasting in a roasting process and metallic metal silicon having a purity of 99% to a particle size of 2 mm or less was used, and starch and water were used as a granulating binder. As the additive, a powder obtained by grinding a waste magnesia furnace material having a MgO purity of 98% to a particle size of 100 μm or less was used. Table 4 shows the chemical composition of the shot blast dust, and Table 5 shows the chemical composition of the aluminum dust roasted dust.

[0033]

[Table 4]

[0034]

[Table 5]

Shot blast dust collection 1 kg, Al
Midarai roasted dust collection dust 125g, metal silicon powder
Powder 150g, water 100g and starch 20g
Mixing with a sir and using a briquetting machine
After forming the reactants by forming into briquettes, air drying
I let it. Magnesia is applied to this naturally dried reactant.
After adding 700 g of decommissioning material powder and loading it into a graphite crucible,
In a silicon knit furnace holding graphite crucible at 1000 ℃
Inserted and heated for 30 minutes. After heating, as in Example 1
Ignited, granulated and classified by various methods, and MgO: 55.
4%, SiO_Two : 25.7%, Al_TwoO_Three: 13.2%
And the remainder is CaO, MnO, FeO, Fe_TwoO_Three, Cr
_TwoO_Three, ZrO_Two, TiO_Two, Na_TwoO and K_TwoO mixing
With a particle size of 0.05 to 2.80 mm
A dense spherical projectile was obtained.

Example 3 Example 2 was used as a raw material for a reactant.
Using the same raw materials as described above, ZrO ₂ purity 95% as an additive
The powder obtained by pulverizing the waste zirconia nozzle of Example 1 into a particle size of 100 μm or less was used. Example 2 Using 1 Kg of shot blast dust, 140 g of aluminum dust roasting dust, 140 g of metal silicon powder, 100 g of water and 20 g of starch.
A reactant was prepared in the same manner as described above. After 500 g of waste zirconia nozzle powder was added to the naturally dried reactant, it was charged into a graphite crucible and heated in the same manner as in Example 2.
Granulation and classification are performed in the same manner as in Example 1, and ZrO
_{2: 45.2%, SiO 2:} . 31 0%, Al 2 O 3:
20.1%, balance is MgO, CaO, MnO, Fe
O, Fe ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , Na ₂ O and K
Chemical composition consisting of a mixture of ₂ O with a particle size of 0.05 to 2.
A dense spherical projection material of 80 mm was obtained.

[0037]

As described above, according to the present invention, since a shot material is manufactured from a molten state at a high temperature by using a thermite reaction, a spherical, non-metal-based shot material having a long life and having no pores is manufactured. can do. Further, the composition of the shot material can be adjusted to a required chemical composition, and a shot material applicable to a wide range of shot blast can be provided. Furthermore, the present invention uses waste as a raw material and thermit reaction heat as energy, so that not only is it possible to produce a projectile extremely economically,
It also enables the recovery of metal resources contained in waste at the same time, and greatly contributes to society from the viewpoint of effective use of resources.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Jungo Kurosaki Nishiharu, Nishi-Kasugai-gun, Aichi Prefecture, Ufuji-ji, Shinmei 51 Fukujiji Shinmei 51 Shinto Breiter Co., Ltd. F-term (reference) 4G004 DA03 4G042 DB09 DB29

Claims (8)

[Claims] 1. A reactant is prepared by mixing iron oxide powder with a powder containing metallic aluminum, or is prepared by mixing a powder containing iron oxide powder with metallic aluminum and then molding the mixture. A thermite reaction is caused by igniting the reactant manufacturing step and the reactant, or one of MgO, ZrO ₂ , SiO ₂ , and Al ₂ O ₃
A reaction step in which a thermite reaction is caused by igniting the above-mentioned reactant to which a seed or two or more kinds of powders are added; a granulation step in which the molten oxide produced by the thermite reaction is granulated in a spherical form; A method for producing a spherical projection material, comprising a classification step of collecting particles having a desired particle size by classifying the obtained particles. 2. A reactant is prepared by mixing iron oxide powder and metal silicon powder to produce a reactant, or by mixing iron oxide powder and metal silicon powder and then molding the mixture to produce a reactant. A thermistor reaction step by igniting the reactant producing step and the reactant, or
O, ZrO ₂ , SiO ₂ , Al ₂ O ₃ , one or more of the above-mentioned reactants to which a powder added is ignited, thereby forming a thermite reaction by a reaction step, and a thermite reaction. A method for producing a spherical blasting material, comprising: a granulating step of granulating a molten oxide into a sphere; and a classifying step of collecting particles having a desired particle size by classifying the granulated particles. 3. The production of a spherical projection material according to claim 1, wherein the powder containing metallic aluminum contains metallic aluminum in an amount of 30% by mass or more, and the equivalent circle diameter of the particles is 10 mm or less. Method. 4. The powder containing metallic silicon contains metallic silicon in an amount of 30% by mass or more, and the particle has a circle equivalent diameter of 1%.
The method for producing a spherical projectile according to claim 2, wherein the diameter is 0 mm or less. 5. The method for producing a spherical blast material according to claim 1, wherein the method for granulating the molten oxide into a sphere is blasting. 6. The composition according to claim 1, wherein the chemical composition is_TwoO_Three: 8
0-20%, SiO_Two: 80 to 10% and Mg
O, CaO, MnO, FeO, Fe_TwoO_Three, Cr_Two O_Three,
ZrO_Two, TiO_Two, Na_TwoO and K_TwoO total is 20%
And the particle size is between 0.05 and 2.80 mm.
A method for producing a spherical projectile according to any one of claims 1 to 5.
A spherical projection material manufactured by the method. 7. The chemical composition is represented by the following formula:
10%, SiO ₂ : 70% or less, Al ₂ O ₃ : 70% or less, CaO, MnO, FeO, Fe ₂ O ₃ , C
The total of r ₂ O ₃ , ZrO ₂ , TiO ₂ , Na ₂ O and K ₂ O is 20% or less, and the particle size is 0.05 to 2.80 mm
A spherical projection material produced by the method for producing a spherical projection material according to any one of claims 1 to 5. 8. The method according to claim 1, wherein the chemical composition is ZrO._Two: 70
Between 10% and 10%_Two : 70% or less, Al_TwoO_Three: 7
0% or less, MgO, CaO, MnO, FeO,
Fe_TwoO_Three, Cr_TwoO_Three, TiO_Two, Na_TwoO and K_TwoO
Is 20% or less and the particle size is 0.05 to 2.80.
mm, and the spherical shape according to any one of claims 1 to 5.
A spherical projection manufactured by a method for manufacturing a shot material.
Shooting material.